Comparison of Histomorphometric Study of Chromaffin Cells in Adult Males Squirrel (Sciurusanomalus) and Hamster (Mesocricetusauratus)

The adrenal glands are endocrine glands that produce a diversity of hormones comprising of adrenaline, the aldosterone and cortisol. The present study aimed at investigation of the histomorphometric features of chromaffin cells. There were two types of chromaffin cells. In squirrel, the first type was columnar in shape and brownish in color contained spherical nucleus located at the base of cells, which represented the epinephrine secreting cells, and the second type was polygonal in shape and light brownish in color contained spherical nucleus located in the center of cells, which represented the norepinephrine secreting cells. The adrenal medulla of hamster consists almost entirely of columnar or polyhedral chromaffin cells forming clusters and anastomosing cords separated by sinusoids, giving a strong reaction with methylene eosin stain more than that seen in squirrel. The statistical analysis showed that the means diameter of epinephrine cells and norepinephrine cells in the right adrenal gland in squirrel were lesser than those of hamster significantly at P<0.05, but in the left adrenal gland in squirrel the means were greater than those of hamster significantly at P<0.05. In conclusion, the present findings showed the reaction of chromaffin cells of hamster with methylene –eosin stain to be stronger than with hematoxylin-eosin stain, while the opposite was true in case of the squirrel.

NUCLEAR MOMENTUM DISTRIBUTION WITH FRACTIONAL OCCUPATION PROBABILITIES OF THE SURFACE ORBITS

Simplified expressions for calculating nucléon momentum distributions are derived in the context of the harmonic oscillator shell model and in its modification in which fractional occupation probabilities of the surface orbits are used. The method is applied to study the proton momentum distribution of the spherical nucleus 40Ca. The values of the partial occupation probabilities used had been previously determined by fitting to the experimental elastic form factor data.

Nuclear distributions, rms radii and form factors with the harmonic oscillator shell model

General expressions for calculating nuclear distributions (proton, charge, matter and momentum), mean radii and nuclear form factors are derived by extending recent related works. They are based either on the simple harmonic oscillator shell model or on its modification in which fractional occupation probabilities of the surface orbits are used to fit the experimental elastic electron scattering data. The 40Ca and the values of partial occupation method is applied to the spherical nucleus probabilities are compared with those determined from experimental reaction data.

Morphology and Morphometry of the Midgut in the Stingless Bee Friesella schrottkyi (Hymenoptera: Apidae)

Friesella schrottkyi is a small stingless bee (3-mm long) important for agricultural and native forest pollination. This study describes the morphology and morphometry of the midgut in F. schrottkyi forager workers. The F. schrottkyi midgut presents a single-layered epithelium with digestive, regenerative and endocrine cells. The digestive cells are similar along the entire midgut length with a spherical nucleus, apex with long striated border, cytoplasmic granules in the apical region and well-developed basal labyrinth associated with mitochondria, suggesting they are multifunctional, synthesizing digestive enzymes and peritrophic matrix compounds and absorbing nutrients. Regenerative cells are located around the basal region organized in nests with some cells with a spherical nucleus. Phe-Met-Arg-Phe-NH2-amide (FMRFamide) positive endocrine cells are restricted to the posterior midgut region, suggesting a paracrine function in the midgut. This is the first morphological description of the F. schrottkyi midgut contributing to the comprehension of the digestive process of this bee.

The Systems of Volume-Localized Electron Quantum Levels of Charged Fullerenes

The existence of a system of short-lived, discrete, volume-localized electron quantum levels in positively charged fullerenes is theoretically and numerically demonstrated using the example of fullerenes C60 and C20. Unlike experimentally and theoretically well-studied electron states localized in a thin surface layer, these electron states are due to the flat part of the Coulomb potential of a positively charged fullerene sphere. The energy width of the system of such discrete volume-localized levels depends on the charge and increases with increasing charge. For C60+1, the energy width is 0.16 a.u. and increases up to 0.9 a.u. for fullerene C60+10. Thus, the electrons captured on these discrete levels of fullerene form a sort of short-lived superheavy “nanoatom” or “nanoion,” in which the electrons are localized inside a positively charged spherical “nucleus” with an atomic mass of 240 a.u. for C20 and 720 a.u. for C60. Numerous published papers have demonstrated theoretically and experimentally the existence of metastable positively charged C60 fullerenes with a charge of +10 or more, which suggests the possibility of experimental observation of the considering system of volume-localized electronic states. In conclusion, questions are discussed and estimates are made of the possibility of generating coherent radiation at these transitions.

Isomers and shell evolution in neutron-rich nuclei below the doubly magic nucleus 132Sn

The level structures of the very neutron-rich nuclei 128Pd82 and 126Pd80 have been investigated for the first time. A new isomer with a half-life of 5.8(8) μs in 128Pd is proposed to have a spin and parity of 8+ and is associated with a maximally aligned configuration arising from the g9/2Pd proton subshell with seniority υ = 2. The level sequence below the 8+ isomer is similar to that in the N = 82 isotone 130Cd, but the electric quadrupole transition that depopulates the 8+ isomer is more hindered in 128Pd than in 130Cd, as expected in the seniority scheme for a semi-magic, spherical nucleus. For 126Pd, three new isomers with Jπ = (5-), (7-), and (10+) have been identified with half-lives of 0.33(4) μs, 0.44(3) μs, and 23.0(8) ms, respectively. The smaller energy difference between the 10+ and 7- isomers in 126Pd than in the heavier N = 80 isotones can be interpreted as being ascribed to the monopole shift of the h11/2 neutron orbit. The nature of the N = 82 shell closure scrutinized with these characteristic isomers is discussed.

Sperm ultrastructure in two species of Brachidontes (Bivalvia, Mytilidae) from the south-western Atlantic Ocean

Brachidontes rodriguezii and Brachidontes purpuratus have a wide geographic distribution along the Argentinean coast. Both species are abundant in the intertidal area of rocky shores. We used transmission electron microscopy to study the spermatogenesis of B. rodriguezii and the structure of mature spermatozoa from B. rodriguezii and B. purpuratus. Our results show that spermatogenesis in B. rodriguezii is very similar to that reported in other mytilids. The spermatozoa of both Brachidontes are of the primitive or ect-aquasperm type showing a spherical nucleus capped by a conical acrosome with an anterior extension. The chromatin was electron-dense, homogeneous and compact. The mid-piece region consisted of 5 spherical mitochondria grouped in a ring around a pair of short cylindrical centrioles. The flagellum exhibit the typical 9 + 2 microtubule structure. Studies of spermatozoa ultrastructure are considered a useful tool in bivalve phylogeny. Characters in the spermatozoa morphology of these two species were observed and a brief discussion about the sperm morphology along the distribution of both species is presented. We suggest that the acrosome complex presents the most significant differences between both species.